1. Field of the Invention
This invention relates to the field of communication by sightless persons, and in particular to a method of communication applicable to sightless persons, sighted persons and mixed sightless and sighted persons.
2. Description of the Prior Art
The use of braille impressions as a means of conveying information to and from sightless persons has long been known. In general, braille is a code in which each of the letters and numerals of the conventional arabic alphabet is represented by a combination of raised dots peculiar to that letter or numeral. The field in which a single letter or numeral is represented is a matrix of six dots, three dots high by two dots wide. Inasmuch as the codes for the letters A through J are the same codes as for the numerals one through nine and zero, an extra code is provided to notify the reader that the code immediately following is to be interpreted as a numeral. A second extra code notifies the reader that the code immediately following is to be read as a capital letter.
Persons who learn to read and write braille become quite proficient in the skill, and are able to quickly read braille text by merely passing their fingers over the raised dots. Apparatus is available for writing in braille, the apparatus operable to raise dots in the chosen combinations on a paper or other medium. By avoiding exactly aligning the matrices of raised braille dots, braille may be "printed" on both sides of a sheet without interference.
Braille has been applied to various conventional devices, whereby such devices become useful to sightless persons. U.S. Pat. No. 2,091,146--Hamilton discloses a braille clock and U.S. Pat. No. 2,289,717--Montgomery discloses a braille slide rule. Both these patents disclose apparatus in which all possible times of day or calculation results are coded by increments on the respective devices, in braille. In the slide rule, a slidable position indicator permits the user to read the result of a calculation as the numeral coded in braille at the position indicated by the slide. In the braille clock, times of day are coded on a rotating dial, and a position indicator marks the current time.
Hamilton's braille clock is also readable by sighted persons, conventional arabic numerals appearing along side the braille impressions. The time conventionally appearing in the space indicated also appears in braille within a marked space.
While Montgomery's slide rule is certainly useful for sightless persons, the device is awkward for sighted persons, unless such sighted persons are also proficient in braille. Hamilton's braille clock, which also employs optically-discernible characters, is readable by sighted persons and sightless persons alike. Nevertheless, even in Hamilton's clock, the device does not form a means of communication between sighted and sightless persons. Rather, the device is adapted to convey information to either sightless persons or sighted persons, and not therebetween.
U.S. Pat. No. 3,784,763--Budrose teaches a universal recording card having ferromagnetic strips for audio recording, the card also having braille impressions thereupon. The braille impressions represent the same information recorded on the audio strip. Although Budrose does not teach a specific use for such dual recordation of information, since aurally and tactilely recorded information are both included, it is presumed that the device is useful for teaching the reading of braille to sightless persons.
None of the foregoing patents teach a method of communication that is likewise applicable to communications between sighted persons, sightless persons, and communications between sighted and sightless persons. There has therefore been a need for a method of communication which can bridge the gap between sighted and sightless persons, yet requires no specialized knowledge unlikely to be available to either of the communicating persons.